It has been reported that (1) retinoids can destabilize membranes, especially lysosomal membranes with the possible subsequent release of hydrolytic enzymes (2) retinoids can increase the fluidity of membranes in a dose-related manner (3) retinoids can possibly form free radicals by the nature of their structure, and (4) retinoic acid can be oxidatively decarboxylated in vitro using incubation conditions similar to those used for the NADPH stimulated peroxidation of microsomal membranes. Based upon this observation studies were undertaken to examine electron donating and electron accepting properties of selected retinoids and to try to correlate these properties to the ability of retinoids to affect membrane peroxidation which, in turn, could be correlated to the ability of retinoids to destabilize membranes.